Nonwoven webs formed by nonwoven extrusion processes such as, for example, meltblowing and spunbonding processes may be manufactured into products and components of products so inexpensively that the products could be viewed as disposable after only one or a few uses. Exemplary products include disposable absorbent articles, such as diapers, incontinence briefs, training pants, feminine hygiene garments, wipes, and the like.
There is an existing consumer need for nonwovens that can deliver softness and extensibility when used in disposable products. Softer nonwovens are gentler to the skin and help provide a more garment-like aesthetic for diapers. Nonwovens that are capable of high extensibility can be used to provide sustained fit in products such as disposable diapers, for example, as part of a stretch composite, and facilitate the use of various mechanical post-treatments such as stretching, aperturing, etc. Extensible materials or structures are defined herein as those capable of elongating, but not necessarily recovering all or any of the applied strain. Elastic materials, on the other hand, by definition, must recover a substantial portion of their elongation after the load is removed.
There exists within the industry today a need for extensible nonwovens with moderate to low denier fibers that can be made from resins without the need for high cost specialty polymers or elastic polymers. It is well known to those trained in the art that as spinning attenuation velocities increase, molecular orientation increases and fiber elongation decreases. For strong, low denier fibers with low elongation, this is not a problem, but producing low denier fibers with high elongation remains a significant challenge. It is therefore an object of the present invention to provide nonwoven webs comprising low denier fibers that can be made from conventional resins without the need for costly additives. It is a further object of the present invention to provide disposable articles comprising such soft extensible nonwoven webs.